Often if a stain has been washed and dried it's set, but one old-fashioned stain remover which has helped me is Fels Naptha. It comes in the laundry section in bars. Rub it into the area and scrub hard or with a brush. Let it sit about 10 minutes, then wash in hot water.

Maybe when he gets new shirts, you need to presoak them (Biz?) to prevent this from happening. I have the same problem with perspiration/antiperspirant stains in the armpits that are impossible to get out. I hope others will have some suggestions for you too.

I think I would have him try a different deodorant, or write to the company and complain, maybe they will have an idea what would take out the hard crusty build-up.

Had one other thought...if he can wear colored tshirts to work, you might try that as I think the stains are less of a problem with colored shirts.

I read this treatment for removing stains from tablecloths in our local paper. You might try it to see if it does the trick.

Set the washing machine on the lowest level of water and use all hot water. Add 1 cup of your laundry detergent, 1 cup of electric dishwashing detergent (I use Cascade), and 1 cup of liquid Clorox bleach. Agitate the clothes for about a minute to dissolve all the soaps and mix them well. Then turn off the machine and let the clothes soak overnight. The next day, run the clothes the entire cycle. Usually that takes care of all stains. I usually treat the stains first with spot treaters (I use a spritz of Folex carpet cleaner usually these days).

NOTE: I have used this recipe without the liquid Clorox bleach too, and it usually works quite well. If the stain is still there a little, do the treatment again before putting it in the dryer, and if you did not use Clorox the first time, you might try adding that or just repeating what you did the first time. Cascade is powerful stuff.

Oxy Brite or Oxy Clean works wonders at removing deordorant stains (and at preventing them in the first place). For stain removal, dissolve Oxy Clean in hot water and soak shirts overnight. Then wash as usual. For prevention, use Oxy Clean each time you wash.

Had the same problem--never could find any answer. But found new deodorant Certain dri 1-800-331-0221

You might want to try a detergent called Charlie's Soap. It's amazing what it will bring out of clothes. I will say that some people have had great luck with it (like me) and others don't think it works well for them. I think your water has a lot to do with how well it works, but for me it kept me from sending back an new FL washer.

Here is a link that might be useful: Charlie's Soap